Recent advances of nanofluids in micro/nano scale energy transportation

As the continuing integration and size deflation of component dimensions in electronic circuits and increase in the number of transistors in modern microprocessor chips, especially for heat dissipation of micro/nano scale devise, traditionally used single phase fluid cannot meet the requirements for highly efficient heat transfer, which thus frequently results in the damage of electrical devices. Consequently, thermal conductivity enhancement of working fluids is of great significance for advanced thermal energy conservation and conversion. Nanofluids, which possess a superior thermal conductive performance, are studied towards an alternative to the traditionally used working fluids, have attracted ample attention within the past decades. In this paper, firstly, we summarized the recent progress in the preparation of nanofluids, in particular for a method involving a covalent concerning reorganization or generation; subsequently, the utilization of nanofluids in hitherto unsummerized micro/nano scale heat and mass transfer fields, especially for some chemistry relating applications were discussed. All works demonstrated in this review are aiming at clarifying the fact that advanced material technologies are required in preparation of recent nanofluids on the premise of continuing harsh energy transfer situation; on the other hand, nanofluids were also able to offer insights for novel micro/nano scale energy transportation which has not yet been reviewed before

Gut Microbiome Dysbiosis in Antibiotic-Treated COVID-19 Patients is Associated with Microbial Translocation and Bacteremia

Although microbial populations in the gut microbiome are associated with COVID-19 severity, a causal impact on patient health has not been established. Here we provide evidence that gut microbiome dysbiosis is associated with translocation of bacteria into the blood during COVID-19, causing life-threatening secondary infections. We first demonstrate SARS-CoV-2 infection induces gut microbiome dysbiosis in mice, which correlated with alterations to Paneth cells and goblet cells, and markers of barrier permeability. Samples collected from 96 COVID-19 patients at two different clinical sites also revealed substantial gut microbiome dysbiosis, including blooms of opportunistic pathogenic bacterial genera known to include antimicrobial-resistant species. Analysis of blood culture results testing for secondary microbial bloodstream infections with paired microbiome data indicates that bacteria may translocate from the gut into the systemic circulation of COVID-19 patients. These results are consistent with a direct role for gut microbiome dysbiosis in enabling dangerous secondary infections during COVID-19

Graphene-based nanocomposites for energy storage and conversion in lithium batteries, supercapacitors and fuel cells

Due to their unique properties, together with their ease of synthesis and functionalization, graphene-based materials have been showing great potential in energy storage and conversion. These hybrid structures display excellent material characteristics, including high carrier mobility, faster recombination rate and long-time stability. In this review, after a short introduction to graphene and its derivatives, we summarize the recent advances in the synthesis and applications of graphene and its derivatives in the fields of energy storage (lithium ion, lithium-air, lithium-sulphur batteries and supercapacitors) and conversion (oxygen reduction reaction for fuel cells). This article further highlights the working principles and problems hindering the practical applications of graphene-based materials in lithium batteries, supercapacitors and fuel cells. Future research trends towards new methodologies to the design and the synthesis of graphene-based nanocomposite with unique architectures for electrochemical energy storage and conversion are also proposed. The Royal Society of Chemistry

Multifunctional CO3S4/graphene composites for lithium ion batteries and oxygen reduction reaction

Cobalt sulfide is a good candidate for both lithium ion batteries (LIBs) and cathodic oxygen reduction reaction (ORR), but low conductivity, poor cyclability, capacity fading, and structural changes hinder its applications. The incorporation of graphene into CO3S4 makes it a promising electrode by providing better electrochemical coupling, enhanced conductivity, fast mobility of ions and electrons, and a stabilized structure due to its elastic nature. With the objective of achieving high-performance composites, herein we report a facile hydrothermal process for growing CO 3S4 nanotubes (NTs) on graphene (G) sheets. Electrochemical impedance spectroscopy (EIS) verified that graphene dramatically increases the conductivity of the composites to almost twice that of pristine CO3S4. Electrochemical measurements indicated that the as-synthesized CO3S4/ G composites exhibit good cyclic stability and a high discharge capacity of 720 mAhg1 up to 100 cycles with 99.9% coulombic efficiency. Furthermore, the composites react with dissolved oxygen in the ORR by fourand two-electron mechanisms in both acidic and basic media with an onset potential close to that of commercial Pt/C. The stability of the composites is much higher than that of Pt/C, and exhibit high methanol tolerance. Thus, these properties endorse CO3S4/G composites as auspicious candidates for both LIBs and ORR. 2013 Wiley-VCH Verlag GmbHandCo

Investigation of Harmonic Response in Non-Premixed Swirling Combustion to Low-Frequency Acoustic Excitations

The propagation mechanism of flow disturbance under acoustic excitations plays a crucial role in thermoacoustic instability, especially when considering the effect of non-premixed combustion on heat release due to reactant mixing and diffusion. This relationship leads to a complex coupling between the spatial distribution of the equivalence ratio and the propagation mechanism of flow disturbance. In the present study, the response of a methane-air non-premixed swirling flame to low-frequency acoustic excitations was investigated experimentally. By applying Proper Orthogonal Decomposition (POD) analysis to CH* chemiluminescence images, the harmonic flame response was revealed. Large Eddy Simulation (LES) was utilized to analyze the correlation between the vortex motion within the shear layers and the harmonic response under non-reacting conditions at excitation frequencies of 20 Hz, 50 Hz, and 150 Hz. The results showed that the harmonic flame response was mainly due to the harmonic velocity pulsations within the shear layers. The acoustically induced vortices within the shear layer exhibited motion patterns susceptible to harmonic interference, with spatial distribution characteristics closely related to the oscillation modes of the non-premixed combustion

Assessing the Suitability of Fractal Dimension for Measuring Graphic Complexity Change in Schematic Metro Networks

Schematization is a process of generating schematic network maps (e.g., metro network maps), where the graphic complexity of networks is usually reduced. In the past two decades, various automated schematization methods have been developed. A quantitative and accurate description of the complexity variation in the schematization is critical to evaluate the usability of schematization methods. It is noticed that fractal dimension (F) has been widely used to analyze the complexity of geographic objects, and this indicator may be appropriate for this purpose. In some existing studies, although F has been employed to describe the complexity variation, the theoretical and experimental basis for adopting this approach is inadequate. In this study, experiments based on 26 Chinese cities’ metro networks showed that the F of all these metro networks have decreased in schematization, and a significant positive correlation exists between the F of original networks and the reduction of F after schematization. The above results were verified to have similar trends with the subjective opinions of participants in a psychological questionnaire. Therefore, it can be concluded that F can quantitatively measure the complexity change of networks in schematization. These discoveries provide the basis for using F to evaluate the usability of schematization methods

Hybrid of Co₃Sn₂@Co Nanoparticles and Nitrogen-Doped Graphene as a Lithium Ion Battery Anode

A facile strategy was designed for the fabrication of hybrid of Co₃Sn₂@Co nanoparticles (NPs) and nitrogen-doped graphene (NG) sheets through a hydrothermal synthesis, followed by annealing process. Core–shell architecture of Co₃Sn₂@Co pin on NG is designed for the dual encapsulation of Co₃Sn₂ with adaptable ensembles of Co and NG to address the structural and interfacial stability concerns facing tin-based anodes. In the resulted unique architecture of Co₃Sn₂@Co–NG hybrid, the sealed cobalt cover prevents the direct exposer of Sn with electrolyte because of encapsulated structure and keeps the structural and interfacial integrity of Co₃Sn₂. However, the elastically strong, flexible and conductive NG overcoat accommodates the volume changes and therefore brings the structural and electrical stabilization of Co₃Sn₂@Co NPs. As a result, Co₃Sn₂@Co–NG hybrid exhibits extraordinary reversible capacity of 1615 mAh/g at 250 mA/g after 100 cycles with excellent capacity retention of 102%. The hybrid bears superior rate capability with reversible capacity of 793.9 mAh/g at 2500 mA/g and Coulombic efficiency nearly 100%

An Analysis of Immunoreactive Signatures in Early Stage Hepatocellular Carcinoma

Background: Hepatocellular carcinoma (HCC) is prevalent worldwide and early diagnosis of HCC is critical for effective treatment and optimal prognosis. Methods: Serum was screened first by immunoproteomic analysis for HCC-related tumor associated antigens (TAAs). Selected TAAs were clinically evaluated retrospectively in patients with HCC, liver cirrhosis, chronic hepatitis and healthy controls. Levels of autoantibody to the selected TAAs were measured by protein microarrays containing protein antigens of the candidate TAAs. Analyses were done by using receiver operating characteristics (ROC) to calculate diagnostic accuracy. Findings: Twenty-two candidate TAAs were assessed by protein microarray analysis in 914 participants with serum α-fetoprotein (AFP) available. Twelve candidate TAAs were statistically different in signal intensity between HCC and controls. Among them, CENPF, HSP60 and IMP-2 showed AUC (area under the curve) values of 0.826, 0.764 and 0.796 respectively for early HCC. The highest prevalence of autoantibody positivity was observed in HCC cases with BCLC tumor stage A, well-differentiated histology and Child-Pugh grade C. Specifically, 73.6% or 79.3% cases of early HCC with negative AFP were positive for autoantibody to CENPF or HSP60. Interpretation: Tumor-associated autoimmune reactions may be triggered by early stage HCCs. Measurement of serum autoantibody to TAAs may be complementary to AFP measurements and improve diagnosis of early HCC